Infection with HIV-1 often leads to the development of neurological problems despite the advent of highly active antiretroviral therapy (HAART). In addition, HIV-infection is frequently associated with the use of addictive drugs, such as Methamphetamine (METH). While both HIV-1 and METH can cause behavioral, neurocognitive and histopathological changes, the potential interaction of virus, HAART and METH is poorly understood, in particular at the cellular and molecular level, and will be studied here. METH and HIV compromise the function of several neurotransmitter systems. HIV-1 envelope protein gp120 binds to macrophages and microglia via CD4 and chemokine co-receptors. HIV/gp120 produces in vitro and in vivo neuronal injury and death, and transgenic mice expressing gp120 in their brain develop neuropathological features similar to AIDS patients. Thus, the central hypothesis is that use of METH aggravates the neurotoxicity of HIV-1 infection and thus compromises the beneficial effect of HAART against HIV infection and the development of HIV-associated neurocognitive disorders. The long-term objective is to improve therapeutic intervention for neuroAIDS. The specific aim is: To characterize the combined impact of Methamphetamine, HIV-1 and HAART on the biological function and survival of neurons. For that purpose we will treat cerebrocortical neurons with combinations of METH, HAART, HIVgp120 and vehicle controls and assess neuronal injury, loss and survival, electrophysiological function, intracellular Ca2+ in response to excitatory neurotransmitter and neuronal vulnerability to excitotoxic insult. Neuronal death and loss will be monitored using microscopy of TUNEL stained nuclear DNA in combination with immunostaining for neuronal markers. Oxidation of protein, lipid and DNA, and active Caspase 3 will be monitored as markers of cellular stress and death signaling. The potential effect of METH, HAART and gp120 in various combinations on signal transduction via stress kinase p38 MAPK and pro-survival kinase Akt may be crucial to an enhancement of HIV/gp120-induced neurotoxicity and will be studied using dominant negative mutants of both kinases. PUBLIC HEALTH RELEVANCE: Infection with HIV-1 is often leads to neurological complications despite highly active antiretroviral therapy (HAART). Moreover, HIV infection is frequently associated with exposure to addictive drugs, such as Methamphetamine (METH), and both are major public health concerns. Our studies will improve the understanding of brain injury caused by the combination of METH and HIV infection in the presence of HAART.